Pneumonia is the leading cause of death in children, accounting for more childhood deaths than AIDS, malaria, and measles combined. Almost all these deaths are preventable if pneumonia is diagnosed and treated correctly. However, the current approach, using paper-based protocols that rely on a clinician's ability to count respiratory rate, has proven inadequate in addressing this problem. Recent evidence has suggested that cell phone-based algorithms can improve adherence to diagnostic and treatment guidelines for pneumonia. Furthermore, studies have shown that algorithms based on respiratory rate alone do not adequately identify children with pneumonia at the highest risk of complications and death. This proposed project aims to use an innovative application of existing technology to combine more accurate measures of respiratory rate, oxygen saturation, and clinical symptoms into a more useful diagnostic algorithm for pneumonia. We seek to improve diagnosis accuracy and management of childhood pneumonia through the development of a cell phone-based tool that will assist health care providers in low-resource settings. This tool will include the cell phone-based integration of the following three components: 1. A step-by-step diagnosis and treatment algorithm grounded in the World Health Organization- sponsored Integrated Management of Childhood Illness protocol to identify children with pneumonia using a combination of symptoms, such as cough and fever. 2. A respirometer that operates within the protocol to more accurately count the number of breaths per minute and guide diagnostic decisions. 3. A pulse oximeter to measure oxygen saturation when applicable and provide clinical support and patient management decisions based on the severity of the condition and the risks associated with hypoxemia. We believe that this combination of biometric measurements and symptom assessment will lead to more accurate diagnosis of pneumonia and provide a quantifiable indication of severity. The algorithm will factor in these measures and recommend appropriate treatment, including drug choice and dosage based on age, weight, and severity of illness.